In a base station of a wireless communication network, the antenna is the port through which radio frequency (RF) energy is coupled from the transmitter to the outside world and to the receiver from the outside world. By using an array of antennas, a number of benefits are expected including improved directionality, higher signal-to-noise ratio (SNR), and better capability of interference rejection for received signals.
Calibration systems play an important role in modern wireless communication systems employing adaptive antenna technologies, such as antenna arrays. Depending on the applications and the signal processing algorithms employed by the base station, antenna array calibration includes determining the characteristics of the RF paths of the base station and using the characteristic data to optimize base station radio transmission and radio reception. Smart antenna systems particularly may benefit from the enhanced system performance that can be obtained from calibration.
In addition to calibrating the antenna array, conventional base stations typically provide for some form of compensation to remove phase effects introduced into signals transmitted from and received by the base station by analog components, filters and the like within the base station. Thus, these conventional base stations generally require not only a process to calibrate the antenna array, but also a process to compensate for the distortions that are a result of these phase effects.
Therefore, there is a need in the art for an improved digital compensation and vector calibration method for wireless networks. In particular, there is a need for a single method for providing both digital compensation and vector calibration for a base station in a wireless network.